Pyrrolo[2,3-d]pyrimidine compounds are inhibitors of protein kinases, such as the enzyme Janus Kinase 3 (JAK3) and are therefore useful therapy as immunosuppressive agents for organ transplants, xeno transplantation, lupus, multiple sclerosis, rheumatoid arthritis, psoriasis, Type I diabetes and complications from diabetes, cancer, asthma, atopic dermatitis, autoimmune thyroid disorders, ulcerative colitis, Crohn's disease, Alzheimer's disease, Leukemia and other indications where immunosuppression would be desirable. The pyrrolo[2,3-d]pyrimidine compounds, pharmaceutical compositions thereof and methods of use are described in co-pending application Ser. No. 09/732,669, filed Dec. 8, 2000, and assigned to the assignee of the present invention, which is incorporated herein by reference for all purposes.